a) Field of the Invention
The invention relates to a drive arrangement for a security system with at least one actuating member which is supported so as to be movable out of an open position into a closing position, and vice versa, and serves to close and/or open locks, locking bolt mechanisms or catch mechanisms and is driven by two reversible electric motors via a geared connection which transforms rotational drive movements into translatory drive movements.
b) Background of the Related Art
In the drive arrangement known from DE-G 90 11 080.3 (FIG. 3), The electric motors provided for the drive of the actuating member act on the actuating member against the action of a spring via a two-armed 1ever which is rotatably supported at the actuating member, the swiveling movements of the 1ever being defined by fixed stops associated with the two lever arms. The 1ever is alternately moved in one direction parallel to itself or in the other direction from is working position into its neutral position. For this purpose, the electric motors ac6ting on the ends of the levers via helical gear units must be switched on jointly to move the actuating member into the locking position, whereas only one motor need be switched on for unlocking.
Such a drive arrangement does not operate with sufficient reliability. For example, there may be a failure of the drive unit itself or the additional transmission devices to the actuating member which are actuated by the drive unit. The drive unit is then no longer fully functional. It can also come about that the power supply to the drive unit is interrupted or that the control or effective chain or signal path may be disrupted and the movement of the actuating member cannot be carried out for this reason so that it is not able to function properly with respect to time and path. Shocks can also disable the spring so that the actuating member is not held at its stops. In security technology, spring-loaded drive members are generally undesirable as structural component parts for locking elements. In addition, such actuating members used in lock technology, i.e. in door or lock bolts, are generally located on the inside of the door, i.e. in an inaccessible region for repairs in case of disturbance.
It is known in principle to provide a plurality of important drives for such actuating members and to trigger them by identical or different signals arriving by separate paths (redundant arrangement) so that, in the event of failure of an actuating path or of the intermediate members associated with it, the actuating member can be moved by the other drive options (see EP O 111 186 B1).
This is relatively simple to accomplish insofar as the drive of the actuating members is effected manually or, e.g., by means of a plurality of electromagnets acting in parallel. However, if the actuating member must apply considerable forces and/or travel defined paths and therefore requires, e.g., electric motors or work cylinders as drive units, there arises the problem of independently coupling a plurality of such drive units, or possibly different drive units, to the actuating member, especially since the drive units must be in a constant working connection with the actuating member, e.g., when blocking one of two engaged electric motors in order to limit the movability of the actuating member.
It is also known in driven lock devices to allocate a lever connection to the lock bolt which, as an actuating member, is normally associated with an electric motor, so that the lock can be mechanically actuated manually in the event of disruption. Such constructions (emergency devices) are costly and require additional space (see DE-G 90 11 080, FIG. 1).